土壤砷污染特点与植物修复探讨

ARSENIC CONTAMINATION IN SOILS AND ITS PHYTOREMEDIATION

土壤砷污染一直是国内外关注的热点,植物修复技术是20世纪80年代提出的利用植物治理土壤污染的一种"绿色技术"。土壤中砷主要以无机态的形式存在,并主要为Al、Fe、Ca等所吸附而产生共沉淀,水溶态的砷含量一般小于总砷的5%。砷污染区的植物砷含量一般高于非污染区,具有耐贫瘠、耐干旱且地带性不是很强的特点。到目前为止,世界范围内已发现3种超富集砷的植物。根据野外调查与分析,利用超富集植物治理土壤轻度砷污染是可行的。

Arsenic contamination in soils has been noted all over the world for its serious toxicity. Phytoremediation technology is a plant-based remediation technique which was raised in the 1980s. Inorganic arsenic has been identified as the main species in soils, mostly co-precipitate with Al, Fe and Ca, and solute arsenic is less than 5% in most cases. The plants on the arsenic-contaminated sites, which often have a higher level of arsenic in their shoots, have some special characteristics, as compared with those in uncontaminated area. They can grow readily on the arsenic-contaminated soils which are often barren and arid, and often have a wide distribution. So far, three plant species which can hyperaccumulate arsenic from soil have been found all over the world. According to the research, using arsenic hyperaccumulator to remove arsenic from lightly arsenic-contaminated soil is promising.